Merriam-Webster's Word of the Day for October 6, 2023 is:

demarcate • \dih-MAHR-kayt\  • verb

To demarcate something is to fix or define its limits or edges.

// Treaty negotiations are underway, and both parties have agreed to accept whatever boundaries are demarcated in that document.

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Examples:

"In the 15th century, farmers on the North Atlantic isle began to mold the severe ecosystem of its coastal plains, building thousands of small, soil-free vineyards and demarcating their boundaries with the black stones of its fiery past." — Shoshi Parks, Smithsonian Magazine, 9 Aug. 2023

Did you know?

It’s reasonable to assume that demarcate inspired the noun demarcation—many a noun has been formed by adding the suffix -ion to an existing verb. But in this case you'd also be wrong; demarcation came first, with the verb demarcate following as a back-formation. We can ultimately thank Spanish for both: the Spanish noun demarcación (from demarcar, "to delimit") was used in 1493 to name a meridian dividing New World territory between Spain and Portugal. (A Spanish-born pope chose a meridian that favored Spain greatly.) Centuries later, English speakers began calling this boundary the "line of demarcation," and eventually applied that phrase to other dividing lines as well. By the early 19th century, demarcation had been verbified to create demarcate.